A History of Silver and Gold
Gary Campbell (Michigan Technological University)
The desire to use silver and gold is an ancient and universal one. Gold was being worked by 6000 BCE and silver by 4000 BCE (Cramb). These two metals are highly prized for their beauty, malleability (softness, or ability to be worked), and resistance to corrosion. The malleability of the metals, particularly gold, limited their initial usefulness to decorative and ceremonial purposes. Gold and silver are rare but widely dispersed around the world; both, especially gold, can be found in a native, unalloyed form although silver is usually recovered from other minerals like galena (more usually a source of lead). Gold can be found in a primary deposit in rock (lode) or in gravel in streambeds where it has been eroded from the primary source and concentrated by natural forces like gravity (this is known as placer or alluvial gold). The earliest users of gold simply picked up pure gold nuggets out of the gravel and worked them. In some cases silver can be recovered with gold in the alloy electrum, or extracted from minerals like galena through a heating process known as cupellation (though this last process requires more sophisticated knowledge of mining and metallurgical technology than producing gold). Cupellation was well established by 2500 BCE (Cramb). [Global Commodities offers additional information on the history of gold and silver from 1880 at GL CE 880 A. Del Mar and 1917 at GL C4 Silver-White].
In order to find larger amounts of silver and gold, early people had to mine primary deposits that outcropped near the surface. The early mines depended on slaves (often prisoners of war) and convicts. One exception was the Inca Empire, where citizens undertook work in the mines as a tax obligation. In this case working conditions were comparatively good, though all mining was usually harsh, dangerous, and very labor-intensive. The mine sites were often in difficult locations, the work was brutal, and the environment was polluted with dust and metals like lead and arsenic. Workers did not survive long in these types of conditions. Difficult mining conditions lasted well into the 1800s CE.